Power exhauster



Aug. 18, 1953 KNUTSON ET AL 2,649,040

POWER EXHAUSTER Filed Nov. l5, 1950 Patented Aug. 18, 1953 UNITED stares TENT OFFICE POWER EXHAUSTER Harold Knutson and Harold G. Knutson,

This invention relates in general to a power exhauster and is more particularly described as a power exhauster for roof openings which is adapted to positively drive contaminated exhaust from a Ventilator type of unit and to prevent a contaminating inlet from following the rotation of the exhaust wheel and from possible reentry to the exhaust duct when the system isI shut down.

An important object of the invention is to provide a power roof exhauster rigidly constructed to withstand high wind velocity and to eiliciently operate against static pressure. k

A further object of the invention is to provide a power exhauster having a motor compartment which is gravity ventilated at all times and in which the motor is separated from the exhausted currents so that it will not be affected thereby.

A further object of the invention is to provide a strong rigidly constructed unit adapted to be 4" secured at its base to an upstanding curb and to provide a rigid mounting for the motor constructed of relatively thin sheet material.

A further object of the invention is to provide an exhauster in which a rotary exhaust fan has Other objects of the invention will appear in the specication and will be apparent from the accompanying drawings in which, v

Fig. 1 is a top View partly in section of a power exhauster in accordance with this invention, as taken approximately on the line l--l of Fig. 2;

Fig. 2 is a side elevation of the structure shown in Fig. 1, some oi the parts being shown in section;

Fig. 3 is a perspective view of one of the vertical supporting struts;

Fig. 4 is a sectional view through one rim and :the adjacent structure of the exhaust fan; and

Fig. 5 is a detail plan view of the motor mounting between adjacent struts.

In a power exhauster of this type, it is desir- :able not only to mount the motor out of the path of the exhaust gases, but also to vprotect .the motor from the weather, particularly from moisture and yet to adequately support the motor and give it gravity ventilation at all times. This is preferably done by attaching the motor to rigidly reinforced supports of sheet material which have the necessary mounting strength, but yet are of thin and light weight material. Usually the material is galvanized sheet steel or aluminum, but may also be copper and stainless steel.

Referring now more particularly to the drawings, a supporting square or rectangular kbase l0 is preferably formed with a downward flangel2 extending on all sides, each side having an outwardly flaring lower edge I4 adapting the entire base to be set over and secured to an upstanding curb iitting within the base.

At the center of the base is an exhaust opening I6 with a cylindrical shell 20 extending upwardly therefrom. This shell is supported by a number of upwardly extending struts 22 each formed of flat sheet material having anges at the edges for stiiening it and securing it to the different parts to which it is connected.

At the bottom is a ange 24 for securing iti to the top of the base Il); at the inner side is a ange 26 extending the full length to which the shell 2e is connected at the bottom; at the outer side is a ange 28 to which an outer shell 30 is connected near the top; .and at the top is a flange 32 at an angular incline and connected to the inside of a conical top or cover 34 which extends at its center above the upper edge of the outer shell 3Q, the lower edge of the cover extending below the upper edge of the outer shell. These struts 22 are arranged axially about the opening IB in the base and the number of struts may be varied depending upon the size ofA the unit and upon the weight of the motor and exhaust fan to be supported. In the present exemplication, only four struts are included, but there may be only three or six, eight or more. It is possible to have only two, but the structure would not be very well balanced.

Between the upper edge of the inner shell 2li and the lower edge of the outer shell 30 is a conical ring comprising a plurality of curved segments 36, each mounted between adjacent struts 22 by means of flanges 38 at the ends of each section 36. The sections are inclined from the inner diameter downwardly and outwardly so that they are actually frusto-conical and substantially lill the space between the upperand lower sleeves. Within the lower sleeve 20 is an oriiice ring 46 secured intermediate the top and bottom of the sleeve 20 and converging inwardly at the top thereof to conne the exhaust draft to the reduced opening of the orifice ring labove which is located an exhaust fan 42 disposed in the vertical space covered by the frusto-conical sections 36. The exhaust fan has an upper ring 44; a lower ring 46 with its inner diameter substantially the same as the diameter of the orifice ring 40 and blades 48 connected to the upper and lower rings and curved or inclined backwardly from the direction of rotation of the fan to impel the exhaust from the inside of the fan outwardly and against the inclined sections 35. At the top of the fan is a plate 53 for limiting the upv-Jar movement of the exhaust through the fan in that direction. Connected to the fan by means of a shaft 52 is an electric motor 5d having its base secured to a plate or support 5S having bent opposite ends 53 by means of which it is attached to the inner flanges 25 of adjacent vertical struts 22 by fastening bolts S9 or other suitable fastening means. At one portion of the outer shell, it is provided with a removable access door E? secured thereto by fastening screws 64. rfhe motor may be serviced through this door.

Near the upper edge of the outer shell 30, just above the lower edge of the cover 34 is an outward strengthening rib ES and near the lower edge of the shell, a similar strengthening rib 10 isV provided which greatly strengthens the combined and connected structure. At its periphery 68, the lower edge of the conical cover 36 preferably terminates at a short distance from o5.,

the outer shell Sil leaving a space between it and the inside of the shell through which water and dirt may pass downwardly engaging the upper surfaces of the inclined defiectors 3E near the bottoms thereof deflecting such materials out- A? wardly from the unit. Connections between the parts are not shown in detail, but usually consist of small screws, nuts and bolts and in some cases the parts may be spot welded together.

When so connected, the entire assembly unit is I light and strong; it is braced in all directions and will withstand high wind pressure from any direction at the outside thereof.

In operation, the motor rotates the fan which draws the exhaust gases from the interior of the vase through the exhaust opening i6 and into the central portion of the fan at the lower end thereof, discharging the gases through the blades 48 in a substantially tangential manner, throwing the gases outwardly between the struts 22 and against the downwardly inclined sections 36 causing the gases to be impelled outwardly below the lower edges of the deflector sections 36 all around the unit.

The motor is amply ventilated at all times by si.

air currents which strike the outer surfaces of the conical sections 36 and deflect the air upwardly into the spaces between the struts 22 within the outer shell Sil. The motor is protected from water storms and dirt by being practically enclosed within the outer shell 39 below the conical cover S4 except at the outer edge, and the motor space being open at the bottom of the outer shell 30.

While a preferred embodiment of the invention has been described in some detail, it should be regarded as an illustration or example rather than as a limitation or restriction of the invention, since various changes in the construction, combination and arrangement of parts may be made without departing from the spirit and scope of the invention.

We claim:

l. In a power exhauster, an inner circular shell and an outer circular shell, a plurality of radial struts between the shells for supporting the shells spaced apart along the struts, an exhaust fan having vertical blades located axially within the inner shell diameter and in the space between the shells for receiving exhaust from the inner shell and expelling it outwardly, and a frusto-conical deflector having its edge of lesser diameter adjacent the top of the fan blades and extending downwardly and outwardly so the eX- haust from the fan strikes the deflector to discharge the exhaust gases.

2. In a power exhauster, an inner circular exhaust shell with inlet and exhaust ends, a plurality of radial sheet metal struts secured to the outside of the shell, each strut having reinforcing flanges at the edges thereof, a power motor secured to the inner flange edges of the struts, an exhaust fan connected to the motor having vertical blades and located at the exhaust end of the shell, the fan having a central inlet from the exhaust shell, means forming a peripheral outlet and a closed end adjacent the motor, and a frusto-conical delector with its edge of lesser diameter adjacent the top of the fan blades and. extending downwardly and outwardly from them and from said peripheral opening to deflect and discharge the exhaust gases.

3. In a circular power exhauster, a plurality of radial struts each formed of sheet material having strengthening flanges at its edges, an inner circular exhaust shell attached to the inner flanges of the struts at one end thereof, an outer shell attached to the outer flanges of the struts at the other ends thereof, a cover for the exhauster connected to the end flanges of the struts and extending nearly to the inner periphery of the outer shell but leaving a fluid discharge space between, a frusto-conical defiector comprising sections mounted between adjacent struts and longitudinally thereof between the inner and outer shells, and an exhaust fan having a motor for operating it, the exhaust fan having an end inlet to receive gases from the inner shell and expel them outwardly against the deflector, and the motor having supporting means for engaging the inner reinforcing iianges of the struts.

4. In a circular power exhauster according to claim 3, in which each of the supporting radial struts is formed of sheet material having strengthening flanges at each of four edges thereof, the flanges providing means for attaching the struts in place.

5. In a circular power exhauster, a plurality of radial struts each formed of sheet material having strengthening flanges at all of its vedges and by which it is attached, one end of the strut being at an inclination to the other opposite end, a conical cover attached to the flange at the inclined end, an outer shell attached to the flange at the end adjacent the cover and extending above the lower edge thereof, an inner exhaust shell attached to the inner flanges of the struts, a supporting base attached to the lower end anges, the center of the base having an opening communicating with the interior of the exhaust shell, and power means supported on the inner flanges of some of the struts comprising a rotatable fan at the upper end of the exhaust shell for receiving exhaust gases centrally from the exhaust shell and discharging them outwardly between the inner and outer shells.

6. In a circular power exhauster, a plurality of radial struts each formed of sheet material with flanged edges and having an inclined extremity at the upper end, an outer shell secured to the outer flanges of the struts and extending upwardly above the lower ends of the inclined portions, a conical cover secured to the flanges of the struts at the upper inclined ends thereof and terminating at a distance inside of the outer shell to leave a peripheral space between the cover and the shell, power means supported by the flanges at the inner edges of the struts for receiving exhaust from the bottom of the struts and expelling it outwardly, and curved deiiector segments each secured at an angle between adjacent struts and forming a deflector for exhaust gases at one side and a deector for material which passes downwardly between the peripheral edge of the cover and the outer shelf at the outside of the deiiector sections.

7. In a power exhauster, a base having a central exhaust opening therethrough, a plurality of sheet material, struts secured to the topv of the base and extending radially outward from the axis of the opening, an inner exhaust shell secured to the insides of the struts adjacent the opening in the base, a power exhaust fan supported by the struts and rotatable about the axis and having one end open at the top of the shell to receive exhaust gases therefrom, and fan blades extending vertically to discharge the gases laterally therefrom as the fan is rotated, an outer shell secured to the outer edges of the struts surrounding the motor, a conical cover secured t0 the upper ends of the struts covering and protecting the motor and terminating at its lower periphery a short distance within the inner periphery of the outer shell, and a frustoconical deector comprising curved sections secured between adjacent struts and each extending from the inside of the strut downwardly to the outside thereof opposite the fan blades to divert the discharge gases from the fan downwardly below the level of the inner shell and outwardly from the exhauster between the struts.

8. In a power exhauster, a supporting base having an outer iiange adapted to i'lt over a supporting curb and an inner exhaust opening, a plurality of struts formed of sheet material extending radially outward from the axis of the opening on top of the base, an exhaust shell secured to the inner edges of the struts over the exhaust opening, an exhaust fan having an end inlet and lateral outlets mounted axially above the shell, an orifice ring near the upper end of the exhaust shell conning the exhaust diameter to that of the opening at the end of the fan, means forming a frusta-conical delector secured between the struts and extending from the top of the fan and downwardly at the outer edge to approximately the level of the upper end of the exhaust shell, a driving motor for the fan having means securing it to the inner edges of the struts above the fan, an outer shell secured to the outer edges of the struts surrounding the motor and extending downwardly approximately to the top of the frusto-conical deflector, and a conical cover for the ventilator secured to the upper ends of the struts covering the motor and terminating at its outer periphery a short distance from the inside of the outer shell so that water, dirt and other materials may pass downwardly therethrough being deflected outwardly from the unit by engagement with the upper surface of the frusto-conical deflector, and the space surrounding the motor being free for air circulation between the struts for cooling the motor.

HAROLD KNUTSON. HAROLD G. KN'UTSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,730,193 Davie et al. Oct. 1, 1929 2,082,955 Hagen June 8, 1937 2,179,893 Lyon Nov. 14, 1939 2,322,302 Martinson June 22, 1943 2,439,124 Bergstrom Apr. 6, 1948 2,526,290 Solzman Oct. 17, 1950 2,582,902 Gohl Jan. 15, 1952 FOREIGN PATENTS Number i Country Date 570,888 Germany Nov. 15, 1931 

